Mongol Derby: Longest, Toughest Horse Race on Earth

Mongol Derby

The Mongol Derby is a bone-crushing sprint through more than 600 miles of rugged Mongolian Steppe. Competitors raced through hailstorms, downpours and oppressive heat in August all on the backs of 800 of wild Mongol horses.

The Adventurists/Richard Dunwoody

Mongol Derby

The Mongol Derby is a bone-crushing sprint through more than 600 miles of rugged Mongolian Steppe. Competitors raced through hailstorms, downpours and oppressive heat in August all on the backs of 800 of wild Mongol horses.

The Adventurists/Richard Dunwoody

Mongol Derby

Riders in the Mongol Derby 2013 at the Awards Ceremony, Aug. 14, 2013. Of the 30 participants, only 18 made it to the finish line.

The Adventurists/Richard Dunwoody

Mongol Derby

The night before the race, derby organizer Katy Willings raised a glass of airag, which is fermented mare's milk, for a toast. As is custom in Mongolia, Willings flicks airag over participant's Natacha Lazareff's mount after finishing the Mongol Derby, Aug. 12, 2013.

The Adventurists/Richard Dunwoody

Mongol Derby

This group of extreme adventurers paid up to $10,000 for the privilege to push their physical and mental limits. Mongol Derby participant Natacha Lazareff takes to the water in Ogii Nuur on leg nine, Aug. 7, 2013.

The Adventurists/Richard Dunwoody

Mongol Derby

Aside from the rough weather, Mongol Derby competitors also dealt with illness, injury and local roadblocks, such as this one on Tsenkher Bridge. All riders and crew had to cross this on the way to get to horse station 12, Aug. 8, 2013.

The Adventurists/Richard Dunwoody

Mongol Derby

The Khurel Baatar family who manage horse station 18, Aug. 9, 2013. Each rider has to go through a series of checkpoints to pick up fresh horses.

The Adventurists/Richard Dunwoody

Mongol Derby

At each station, a veterinarian performs a thorough check-up on each rider's horse. If the horse's heart rate is too high, the rider has to stay put until the horse's heart rate returns to normal, costing precious time.

The Adventurists/Richard Dunwoody

Mongol Derby

This year was the race's fifth installment and for the first time, two young women, Devan Horn and Lara Prior-Palmer, both pictured here, were locked in battle for first place -- an unlikely rivalry that ended with a shocking twist, leaving one ecstatic and the other in agony.

The Adventurists/Richard Dunwoody

Mongol Derby

Lara Prior-Palmer chasing Devan Horn on the last leg of the Mongol Derby, Aug. 10, 2013. She started the leg around 10 minutes behind. Tune into "Nightline" to find out what happens.